Replace dangerous (mutable) default value.

topydo/lib/Command.py

@@ -70,7 +70,9 @@ class Command(object):
 
         return value
 
-    def getopt(self, p_flags, p_long=[]):
+    def getopt(self, p_flags, p_long=None):
+        p_long = p_long or []
+
         try:
             result = getopt.getopt(self.args, p_flags, p_long)
         except getopt.GetoptError as goe:

topydo/lib/PrettyPrinter.py

@@ -58,7 +58,7 @@ def pp_color(p_todo_str, p_todo):
 def pp_indent(p_indent=0):
     return lambda s, t: ' ' * p_indent + s
 
-def pretty_print(p_todo, p_filters=[]):
+def pretty_print(p_todo, p_filters=None):
     """
     Given a todo item, pretty print it and return a list of formatted strings.
 
@@ -70,6 +70,7 @@ def pretty_print(p_todo, p_filters=[]):
 
     Example is pp_color in this fle.
     """
+    p_filters = p_filters or []
 
     todo_str = str(p_todo)
 
@@ -78,9 +79,10 @@ def pretty_print(p_todo, p_filters=[]):
 
     return todo_str
 
-def pretty_print_list(p_todos, p_filters=[]):
+def pretty_print_list(p_todos, p_filters=None):
     """
     Given a list of todo items, pretty print it and return a list of
     formatted strings.
     """
+    p_filters = p_filters or []
     return [pretty_print(todo, p_filters) for todo in p_todos]

topydo/lib/View.py

@@ -42,8 +42,9 @@ class View(object):
         for _filter in self._filters:
             self._viewdata = _filter.filter(self._viewdata)
 
-    def pretty_print(self, p_pp_filters=[]):
+    def pretty_print(self, p_pp_filters=None):
         """ Pretty prints the view. """
+        p_pp_filters = p_pp_filters or []
         pp_filters = [self._todolist.pp_number(), pp_color] + p_pp_filters
         return '\n'.join(pretty_print_list(self._viewdata, pp_filters))